Cool game! Please note that I played it on Linuxl.
Like you asked I tried to keep track of the RAM usage. It started off at ~3.4Gib. Was at this value on the planet and also after I launched into space. At some point in space it raised to about 4GiB, and stayed around there afterwards. I think the next time I checked after when i launched into space was before going into the nebula. Landing back on the planet didnt seem to lower it. When I relaounched the game to check something it was back to 3.4GiB.
So I missed the tutorial initially and stated what I think if the main campaign. Starts by talking to the guy in the chapterhouse right? The basic text tutorial that pops up when first launching into space and following the mission was enough for me to figure out how to do most things. I did take a screenshots of the text though since keeping track of all the keys and what they do when introduced at once would have been a bit much. Went back and payed the tutorial after but only stuff that was new to me at that point was stuff like shooting heavy weapons and calling allies. Both of which I think I couldn't do yet anyways?
For the mission I got to the point where you go into the nebula and fight the enemies there. Wasn't sure where to go after that to continue the story so just explore around for a bit, but more or less left it there for now.
Some glitches I ran into:
For the tutorial the voice acting cuts of early for all the lines
So I played the game on Fantastic graphics, and figured id load it up with lower quality settings to tell you the RAM usage. (In hindsight I graphics are loaded to the graphics card's RAM.) But the game would keep crashing when I tried loading my save using different graphics settings. It loaded fine on Fantastic.
The allies in the missions would keep flying into me after combat. Looks like they wanted to be flying near me, but when I was also stationary it would result in them bumping into me.
had a visual glitch, see pic below. Turning off bloom fixed it.
Thanks for the cool demo and good luck with the game!